Chemical formulae, equations and calculations

What is the symbol for relative atomic mass?

• M_r

• R_m

• ^RAM

• A_r

This equation is not balanced:

Mg + O₂ ==> MgO

Which is the correctly balanced equation?

• 2Mg + O₂ ==> 2MgO

• Mg + O ==> MgO

• Mg₂ + O₂ ==> 2MgO

• 2Mg + O₂ ==> Mg₂O₂

To find the M_r you must add together the atomic numbers of the atoms in the formula.

• True

• False

How many atoms are in the formula of ammonium phosphate?

(NH₄)₃PO₄

• 12

• 18

• 20

• 14

What is a mole? Pick two answers.

• 6.02x10²³ particles of a substance

• 1g of carbon 12

• The formula mass of a substance in grams

• The number of particles in 6.02x10²³g of carbon-12

What is the formula mass of Al₂O₃?

A_r(Al) = 27 ; A_r(O) = 16

• 43

• 102

• 70

• 75

Which substance has a formula mass of 44?

A_r values: Na=23; O=16; H=1; Mg=24; C=12

• NaOH

• MgO

• C₃H₆

• CO₂

C₃H₈ + O₂ ==> 3CO₂ + 4H₂O

Carbon dioxide and water are the (a)   in this reaction.

Check the boxes that show the reactants in this reaction:

HCl + NaOH ==> NaCl + H₂O

• Sodium hydroxide

• Water

• Hydrochloric acid

• Sodium chloride

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